JP2606712B2 - Lubrication method of the outer peripheral surface of laid pipe in the grinding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for imparting lubricity to an outer peripheral surface of a laid pipe when a pipe is propelled underground by a grinding method.

(Prior Art) When a laid pipe is propelled into the ground by an augmentation method, when the geology is a clay layer or a loam layer, these are in close contact with the outer peripheral surface of the laid pipe and greatly hinder rotation and propulsion of the laid pipe. When the geology is a sandy layer, the frictional resistance becomes large. In such a case, if it is attempted to grind against these, a strong thrust and rotational torque are required, and as a result, various facilities, equipment, etc. become unnecessarily large compared to the grinding scale.

For this reason, conventionally, the diameter of the head at the tip is set to be larger than the outer diameter of the subsequent laying pipe, and when cutting is performed, the clearance between the head and the ground is secured by the diameter difference. Thus, the contact between the outer peripheral surface of the laying pipe and the ground was minimized.

(Problems to be Solved by the Invention) However, according to such a method, when the cutting distance is long, contact between the laid pipe and the clay layer or the sand layer cannot be avoided due to the earth pressure of the ground. Not much effect can be expected in distance cutting.

For this reason, it is conceivable to increase the diameter difference between the diameter of the head at the tip and the diameter of the laying pipe. However, there is a risk of causing land subsidence, and this is not a drastic solution.

So, without increasing the diameter difference,
It is important to realize smooth cutting even in long-distance cutting in a clay layer.

(Means for Solving the Problems) The present invention has been made in view of the above points, and has been made in consideration of the difference between the diameter of the head at the tip and the diameter of the laying pipe, and the ground formed behind the head at the tip. By using a clearance, an appropriate liquid is constantly injected into the clearance, and this is made to function as a lubricant, so as to reduce the resistance due to the close contact with the clay layer.

As for the specific configuration adopted by the present invention,
In a grinding method using a tip head whose diameter is larger than the outer diameter of the laying pipe, an outer pipe having an inner diameter larger than the outer diameter of the head is exposed at one end opening into the starter shaft. Buried in the ground at the base of the starting side, further discharge the sediment in the outer pipe, insert a laid pipe into this outer pipe,
The gap between the opening and the outer periphery of the laid pipe is sealed to form a waterproof structure, a liquid is injected from the starting shaft into the outer pipe by an appropriate pressure, and the liquid is injected into the gap between the inner circumference of the outer pipe and the outer circumference of the laid pipe. The present invention is characterized in that the gap between the ground and the outer periphery of the laying pipe, which is formed behind the tip head following the gap, is always filled.

Here, the liquid to be injected into the outer pipe may be water, bentonide or the like when the geology is a clay layer or a loam layer, but water is the most preferable in view of inexpensiveness and post-treatment. On the other hand, if the geology is a sandy layer, bentnite is preferred.

In addition, the hermetically sealed waterproof structure between the outer pipe and the outer circumference of the laid pipe is used at the insertion port in the starting shaft in the conventional grinding method.
The technology of the waterproof mechanism used in the waterproof box can be applied as it is.

(Operation) Since these liquids are filled in the gap between the inner circumference of the outer pipe and the outer circumference of the laid pipe in the outer pipe while maintaining an appropriate pressure,
If the installation pipe is cut from the inside of the outer pipe as it is, the liquid immediately spreads from the outer pipe to the clearance due to the difference in diameter caused by the head at the tip, and this liquid is installed as a lubricant. The contact between the outer circumference of the pipe and the ground is smoothed, and the frictional resistance due to clay or the like is greatly reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 and FIG. 2 are diagrams relating to the first embodiment. First, the outer pipe 1 is directed from the inside of the starting pit 2 to the side wall to be cut, and the rear end thereof is set in the starting pit. The sediment in the outer pipe 1 is discharged into the starting pit 2 while remaining in the propulsion burial 2. The outer end of the outer end of the outer tube 1 that remains inside the starting shaft 2 has an inlet 3 communicating with the inner periphery of the outer tube 1.
Is provided. Then, as shown in FIG.
Is connected to a water supply pipe 5 from a water storage tank 4 installed on the ground.

Thus, the laying pipe 7 having the correction head 6 as a head at the head is inserted into the outer pipe 1 thus configured and embedded in the side wall. The outer diameter of the correction head 6 is naturally smaller than the inner diameter of the outer tube 1, and the outer diameter of the installation pipe 7 is smaller than the outer diameter of the correction head 6.

After the laying pipe 7 is inserted, a waterproof mechanism 8 is formed between the rear end opening of the outer pipe 1 and the outer peripheral surface of the laying pipe 7. The technology of the so-called waterproof box used in the above is applied as it is, and the technology fulfills a sufficient function.

After forming such a waterproof mechanism 8, the water supply pipe 5 is connected to the inlet 3, and the water 9 is supplied from the water storage tank 4.
Is injected into the outer pipe 1 by natural fall and filled, and then the correction head 6 and the laying pipe 7 are rotated and propelled on a predetermined course by a normal cutting method.

If the cutting is performed as it is, a gap is formed between the correction head 6 and the laying pipe 7 and the ground behind the correction head 6 due to the difference in diameter. Since the space 9 is filled with the falling pressure, the water 9 immediately enters the space as soon as the space is formed. In view of the speed of propulsion in the drilling method, it is possible to sufficiently cope with the water pressure caused by natural fall, and the intrusion is guaranteed. Of course, the pressure may be increased by an appropriate pump or other pressurizing device as needed.

The water 9 that has entered the gap functions as a lubricant between the outer periphery of the laying pipe 7 and the ground, so to speak, even when the ground is a clay layer or a loam layer, the water 9 contacts the laying pipe 7. However, the frictional resistance is greatly reduced, and the adhesion can be prevented. Therefore, under the same conditions, the grinding method can be performed with a smaller thrust and a smaller rotational torque than the conventional ordinary grinding method.

It is to be noted that, since ordinary water was used as the lubricant in the above-described embodiment, post-treatment after the completion of the construction is not troublesome and there is no problem of pollution such as industrial waste, which is preferable.

(Effect of the Invention) According to the present invention, even if the geology is a clay layer, a loam layer, and a sand layer in a long-distance excavation, it is hardly affected by the lubrication of the liquid, and a smooth excavation method Can be performed. Therefore, the thrust and the rotation torque required under the same conditions in the past can be reduced, and the efficiency is high.

In addition, it can be applied to a normal grinding method as it is, and does not require any special technology for its implementation, and is extremely practical.

[Brief description of the drawings]

Each figure relates to an embodiment, and FIG.
FIG. 2 is an explanatory side view showing the construction status of each embodiment. In the figure, 1 is an outer pipe, 2 is a starting shaft, 3 is an inlet, 4
Is a water storage tank, 5 is a water supply pipe, 6 is a correction head, 7 is a laying pipe, 8 is a waterproof mechanism, and 9 is water.

Claims (1)

(57) [Claims] 1. A grinding method using a tip head having a diameter larger than an outer diameter of a laying pipe, wherein an outer pipe having an inner diameter larger than the outer diameter of the head is connected to a shaft on the starting side. It is buried in the ground of the starting side base so as to be exposed inside, further discharges the earth and sand in the outer tube, inserts the laid tube into the outer tube, and seals the gap between the opening and the outer periphery of the laid tube. And a liquid is injected into the outer pipe from the starting shaft by an appropriate pressure, and the liquid is injected into the gap between the inner circumference of the outer pipe and the outer circumference of the laid pipe and the ground formed behind the tip head following the gap. A lubricating method for an outer peripheral surface of a laid pipe in a cutting method, wherein a gap between the outer pipe and the laid pipe is always filled.